1. Field of the Invention
The present invention relates to a window glass having a dark-colored film for an automobile which is particularly suitable for use with a high mount stop lamp or brake lamp.
2. Discussion of Background
In recent years, glass for an automobile have been provided with various heat ray reflecting films or light ray shielding films for the purpose of providing comfort, design excellence, interior privacy at the inside of a car and the like. Above all, much of dark-colored glass of which visible light transmittance is not more than 70%, has been adopted for a rear glass, a side rear glass and the like which are disposed out of the driving visual scope. The dark-colored glass is excellent for providing comfort in a car room (or car interior), the reduction of air conditioning load, the selectability of color tone showing a luxury feeling, the excellent design, the protection of interior privacy in a car room and the like.
The main stream in the production of conventional dark-colored glass is as follows. In producing plane glass mainly by the floating method, so-called on-line dark-colored glass which is a glass made by the conventional method is provided with a dark-colored film composed of metal oxides firmly coated (by baking) on a surface on one side thereof by a spray method or the like, immediately after glass comes out of a floating furnace, with a glass temperature of 400.degree. to 500.degree. C. (strain point of glass). The on-line dark-colored glass is cut into a developed plane shape of a curved rear or side glass, then printed with a colored ceramic frit paste for a light shielding layer at the peripheral portion thereof and a heat wire silver paste for an electric heating defogger, and is then formed into a predetermined curved shape at an elevated temperature of 600.degree. to 680.degree. C. by employing a bending mold in a glass forming furnace.
Further, in recent times, providing another stop lamp (high mount stop lamp) on a rear spoiler, the top portion of a car body, a rear dash board or the ceiling in a car, other than a normal stop lamp, is extremely effective in cautioning a succeeding car, particularly when driving at night, in rain-fall, in snow-fall and in fog. A mounting ratio thereof for a new car is increasing. In the United States, the mounting thereof is already obligatory in registration.
However, when the high mount stop lamp is provided inside of a car and the dark-colored glass is employed for the rear glass, the visible light transmittance of the dark-colored glass is low, since the conventional dark-colored glass is formed with the film all over the surface of glass owing to its production method. Therefore, the light quantity transmitted from the high mount stop lamp light emitter to the outside of a car is deficient and the light emitted from the high mount stop lamp is reflected by the dark-colored film and is diverged to the inside of a car. Therefore, the high mount stop lamp installed in a car and the dark-colored glass are somewhat compatible with each other. When the dark-colored glass is adopted in the rear glass, there is a restriction in that the high mount stop lamp should be provided on the body outside of a car room or on the rear spoiler, and the like.